Hydrodynamic interaction of axial turbomachine cascades

Abstract

Hydrodynamic interaction of mutually moving airfoil cascades is investigated. It is shown that the semiempirical theory of potential-vortical interaction of two mutually moving cascades in incompressible flow allows one to describe correctly the features of their mutual effect for various gaps between cascades and relations of their pitches. Application of the above theory to a flow around three cascades of the stator-rotor-stator type allows to determine the basic mechanism of the stators' mutual shift effects (clocking effects). To close the theory regarding the vortical interaction of cascades, a semi-empirical model of turbulent diffusion in a non-uniform flow of the periodic vortices descending from airfoils is proposed. Theoretical results are compared with data from numerical and physical experiments. Comparison with results of numerical modeling is based on the solution of the Reynolds equations for a viscous gas closed by the (q-ω) model of turbulence. Results published here and elsewhere are used for comparison with measurement data.